Glass tube bending apparatus



July 19, 1949. A. GREINER Y GLASS TUBE BENDING APPARATUS 2 Sheets-Sheet1 Filed March 30, 1946 Hiya Invavtov: AL fved Gr einer His A t tovficeg.

July 19, 1949. A. GREINER 2,476,658

GLASS TUBE BENDING APPARATUS Filed March 50, 1946 v 2 Sheets-Sheet 2lnvewiiof L Fved Gveina,

Patented July 19, 1949 MT D STATES PATENT OFFICE v TCGVLASS TUBE .2;APFARATU i Q i to General Electric Company, a corporation of New York 1Application March 30, 1946, Serial No. 658,506

6 Claims.

My invention relates to apparatus for bending glass tubing and moreparticularly to apparatus for forming an angular bend in a glass tube.The apparatus is particularly useful in the formation of'U-shaped tubessuch as are used to .2 7 ing from the front face of the bracket '2 andprovided with an axial bore 6 extendin therethrough. The said stud 4extends through the bracket wall I and is fastened thereto in any 5suitable manner, as by a nut 8 threaded onto form the envelopes ofcertain types of electric the projecting rear end portion of the stud.discharge devices, such as germicidal lamps, for Extending through andreciprocable within the instance. bore 6 is a forming pin 9 around whichthe glass The bending of glass tubes into U-shape, when tube H3 is bentduring the operation" of the apperformed by hand, ordinarily requiresthe serv- 10 paratus. The said pin 9 is preferably made of a ices of ahighly skilled glass worker. This is suitable material, such asstainless steel for inparticularly true where it is desired to obtain U-stance, which will not corrode when heated. The tubes of uniform finalshape. 'Such hand bendpin 9 is normally held in a retracted or back ingof glass tubes, however, besides being slow position, with its front endll nearly withdrawn and difficult, is also a costly operation. Moreintothe stud 4, by the expansive force of a comover, where the glass tubesare to be bent into pression coil spring l2 mounted on the pin and-tubes of the type having a very sharp bend, compressed between the'stud(l and a head I3 i. e., with their legs extending closely alongsideformed on the rear end of the pin. During the one another, the glass atthe inner side of the operation of the apparatus, the pin 9 is movedbend is apt to buckle or corrugate during the forwardly, against theresistance of the spring, bending operation because of the excessivecomby suitable foot-operated mechanism l4 comprispression to which it issubjected during such ing a foot pedal IS the swinging end of whichoperation. is connected, by a verticallyextending connect- One object ofmy invention is to provide aping rod l6 extendingup through an openingl6 paratus for forming an angular bend in glass in the table 3, to thefree end of an arm ll tubes and the like by means of which such tubesfastened on a horizontal shaft 18. The said shaft may be quickly andaccurately bent into uniform i8 overlies the pin 9 and is journalled inbrackets shape without collapsing of the tube at the point is mounted onthe rear side of the bracket wall I. of bend- Fastened on the shaft I8is an operating arm 28 Another object 'of my invention is to provide 30provided with an enlarged ball-shaped end 2! apparatus of the above typefor bending glass which engages the rear surface of the head 13 tubesinto uniform U-shape, and particularly on the forming pin 9. When thefoot pedal l5 into U-tubes, having a very sharp bend, without isdepressed, the shaft [8 is rotated to thereby buckling the glass at theinner side of the bend. cause the operating arm 20 to push the formingStill another object of my invention is to propin 9 forwardly to itsoperative or tube bending vide apparatus of the above type which issimple position. v and inexpensive and which will not require Adjacenttheir outer ends, the swivel arms I skilled labor to operate. a areprovided with support pins 22 which project Further objects andadvantages of my invenrearwardly from the arms through arcuate slotstion will appear from the following description 40 23 which areformed inthe bracket wall 1 conof a species thereof and from the accompanyingcentric with the pivot axis P of the arms I. The drawing in which: slots23 are of sufficient arcuate extent to permit Fig. 1 is a frontelevation of apparatus comthe swivel arms I to be swung upwardly toaverprising my invention; Fig. 2 is a plan view tical side-by-sideposition as indicated in dashthereof; Fig. 3 is a rear elevation of theappadot lines in Fig. 1. The swivel arms I .are norratus; Fig. 4 is avertical section on line 44 of mally supported in positionsextendinghorizon- Fig. 3; and Fig. 5 is an elevation of the finishedtally away from each other by the engagement glass U-tube formed by theapparatus comprisof the pins 22 with the lower ends of the slots 23. mgmy invention. The pivot axis P of the arms 1 is offset'relativeReferring to the drawings, the apparatus there to the arms so as to liein the plane of the upper shown comprises a pair of swivel arms I, Ipivotally mounted on an upstanding channel-shaped support bracket 2fastened to the table portion 3 of a bench or stand. The swivel arms Iare pivoted at one end on a headed stud 4 projectsides 24 (Fig. 1) ofthe said arms when they are in their normal horizontal position. 7

During the operation of the apparatus, the swivel arms I are swungupwardly about their common pivot axis P by suitable actuating mech- 3anism 25 comprising a vertically extending rod 26 which is supported inand vertically reciprocable within a bearing 21 fastened on the rearside of the bracket wall 1. At its upper end, the rod 26 carries or isformed with a cross arm or bar 28 the opposite ends of which areconnected by a pair of links 29 to the projectin rear end portions ofthe pins 22 rontherarms l. At its lower end, the rod 25 is connectd'tothe free or swinging end of a foot pedal 30 by a chain, flexible wire orwire band 3| running over a pulley 32 mounted on the underside of thetable 3. When the foot pedal 38 is depressed, the rod 28 is movedupwardly to cause the links 291to gPLlSh upwardly on the arm pins 22 andthus pivot or swing the arms I upwardly about their common pivot axis P.

Adjacent their outer end portions, the arms i each carry suitable holdermeans 33 for supporting the straight glass tube ID- which is to be bent.In the particular case illustrated, the glass tube i is in the formof-an envelope for an electric discharge device such as aggermicidallamp, the envelope [0 being provided at its ends with outwardlyextending exhaust tubes 34 and 35 one of which (tube -35)'iis tippedoff. The holder means 33 are arranged tosupportthe glassenvelope it in aposition extending horizontally alongside and in front. of v the arms Iwhen :the latter are in their normal .lowered position, with theenvelope [0 oifset downwardly with:respect to the pivot axis'P-oithe'arms-a distance sufficient to clear the "forming pin '9 when thelatter is advanced to its operative or tube-bending position overlyingthe glass envelope. I

The;holder:means.33 on each arm Lcomprise-s a pair of V-bl-ocks orplates 36 spaced apart longitudinally of the arm and extending forwardlytherefrom. The forward ends-oithe plates 35 are formed with V-notches314mg. 4) which are aligned longitudinally ,of the arm I and are adaptedto receive the glass envelope it therein. Pivotally mounted on each armbetween the pairof V-plates SB thereon, is a normally springclosed'clamp38- which resiliently engages the front side of the envelope In to holdthe envelope in place within the V-notchest'i.

Mounted adjacent the front side of the bracket wall 1 is-a pairof gasburners 39 for heating the envelope It when it is supported in place onthe horizontally positioned-swivel arms i. The burners 39 aresupported'on opposite sides of the envelope l0 (preferably in positionsdirectly above and below the envelope, as shown) to heat the portionsof-the envelope lying in and adjacent to a plane extending transverselyof the envelope and including the pivot axis P of the arms 5. Theburners 39 are so constructed as to heat the envelope ill more or lessuniformly therearound and are provided with rigidymetal supply pipes orconduits 4B which support the burners in place from an arm mounted onand'extending from the side of the bracket 2. The conduits d9 arepivotally mounted onthe bracket 2 to pivot about a common vertical axl'sso as to enable the burners to belswung'to one sideias indicated indashdot lines in Fig. 2) ont of the path of movement of the glassenvelope Ill and holders 33 when the swivel arms I "are swung'upwardlyto bend the envelope. The conduits 40 are provided with connections 42which areco'nnected to the gas supply for the burners. I

To prevent collapsing of the glass envelope H3 at the heatedregionthereof, air or other gas under a slight pressure may be introduced intothe envelope through the open or untipped exhaust tube 34 thereof. Forthis purpose, one end of a length of rubber tubing 43 may be connectedto the open end of the exhaust tube 34 and the other end of the tubing43 either provided with a mouth piece 44 for the operator to blow intoor connected through a push button valve to a source of compressed air.

In the operation of theiappanaitusnthe glass envelope lfl to be bent isfirst inserted in the holders 33 and centered or otherwise adjustedlongitudinally therein to the proper position for bending. Therubbertubing 43 is then connected to the open exhaust tube 34, after which thegas burners 39 are swung to their envelope-heating position tothereby-heat and soften the portions of the glass envelope lying in andadjacent to the transverse plane including the pivot axis P of the armsi. During'theheating and softening of the envelope H3, air or othergaseous medium is in= troduced as needed into the envelope, through therubber tubing 43 and exhaust tube-:34, i prevent collapsing of thesoftened portion of theienvelope. When the glass envelope hasbeen-softened to the required degree for properv bending; the burners 39are swung to one side to discontinue theheating of theenvelope whereuponfirst the foot pedal i5 is depressed to move the-forming pin 9 inrwardlyto its advanced position overlying the-em velope and then the other:foot pedaalraiiimlnedi ately depressed toswing'the swivel :arms. 1 upwardly to a vertical :side by-sideip'osition as indicated by the arrowsin Fig. 1, =thustbending the glass envelope i=9 around-the forming pin'9 into the U-shape shown inEig.-5.

The forming pin 9 serves to round outthegl'ass at the inner side .of thebend as-indicatedz at 4'5 in Fig. 5. The pin 9 thusprevent-s theformation of an overly sharp bend in. the glass 1 at the inner side ofthe bend. Such a sharp ben dwou'l'd c'ause the glass to buck-leercorrugatev'atthe inner :side of the bend due to theexcessive-compression of the-plastic glass at-such region. The formingpin 9 eliminates this condition by shaping tlre glass into a bend 45 0flarger radius thanit otherwise would have if the forming. pin were not;present.

What I claim as new and desireto secure by Letters Patent of theUnitedfitates is:

1. Glass tube bending apparatus comprising support member carrying aforming pin having a fixed operating position on said support member,tube holding means having spaced .apartzporti'ons thereof on oppositesides of said pin constructed and arranged to gripa tube and holdi'tacross the said pin and offset to one side thereof, the said portions ofsaid holding means being mounted on said support member for simultaneousswinging movement in opposite directions about a common axis ofiset tothe-same siderof the. tube as the said pin to bendthe-tubexaround"thepinwhile the latter is .fix'ediin" itssaidroperating position, and meansfor heating. andsoitenin'g a zene of said tube adjacent the saidpin-prior -tothe swinging movement of-s'aidp'ortien's "of the holdmmeans.

2. Glass tube-bending 'apparatus'comprising a support member carrying apivot pin, a pair or swivel arms each mounted-at one end on said pin tonormally extend therefrom in opposite directions, means on said armsfor. gripping a glass tube'and supporting it 'in a. position such thatitextends along the "faces oi the .arms and oiiset from theaxis ofsaidpin, and means for. heating-and softening aszon'e Of-zthfi tube-adjacentsaid pivot pin, said arms being arransedtocb'e the arms and ofiset fromtheir pivot axis, means for heating and softening a zone of the tubeadjacent the pivot axis of said arms, and a forming pin arranged to bepositioned across the tube on the same side thereof as the pivot axis ofthe arms, said arms being arranged to be swung about their pivot axis ina direction to bend the tube around the said pin.

4. Glass tube bending apparatus comprising a support member, a pair ofswivel arms each pivotally mounted at one end on said support member topivot about a common axis, said arms normally extending oppositely awayfrom each other and having means for gripping a glass tube andsupporting it in a position extending alongside the arms and ofiset fromtheir pivot axis, means for heating and softening a zone of the tubeadjacent the pivot axis of said arms, and a forming pin extendingtransversely of the plane of pivotal movement of said arms and movablelongitudinally from a normally retracted position removed from the glasstube supported on said arms to an advanced operative positioncontinguous to and extending across the tube on the same side thereof asthe pivot axis of the arms, said arms being arranged to be swung abouttheir pivot axis in a direction to bend the tube around the said pin.

5. Glass tube bending apparatus comprising a support member, a pair ofswivel arms each pivotally mounted at one end on said support member topivot about a common axis, said arms normally extending oppositely awayfrom each other and having means for gripping a glass tube andsupporting it in a position extending alongside the arms and ofiset fromtheir pivot axis, means for heating and softening a zone of the tubeadjacent the pivot axis of said arms, a forming pin extendingtransversely of the plane of pivotal movement of said arms and normallylocated in a retracted position removed from the glass tube supported onsaid arms, and pin actuating means for moving said pin longitudinallyfrom its said retracted position to an advanced operative positioncontiguous to and extending across the tube on the same side thereof asthe pivot axis of the arms, said arms being arranged to be swung abouttheir pivot axis in a direction to bend the tube around the said pin.

6. Glass tube bending apparatus comprising a support member, a pair ofswivel arms each pivotally mounted at one end on said support member topivot about a common axis, said arms normally extending oppositely awayfrom each other and having means for gripping a glass tube andsupporting it in a position extending alongside the arms and offset fromtheir pivot axis, means for heating and softening a zone of the tubeadjacent the pivot axis of said arms, a forming pin extendingtransversely of the plane of pivotal movement of said arms and normallylocated in a retracted position removed from the glass tube supported onsaid arms, pin actuating means coacting with the said forming pin tomove it longitudinally from its said retracted position to an advancedoperative position continguous to and extending across the tube on thesame side thereof as the pivot axis of the arms, and arm pivoting meansconnected to said arms for pivoting them about their pivot axis in adirection to bend the tube around the said pin.

ALFRED GREINER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 785,082 Brinkman Mar. 21, 19022,420,119 Boehm et al May 6, 1947

